Coiled tubing conveyed tool strings for treating well intervals or zones are known. See for example, U.S. Pat. No. 4,913,231, Muller and Randermann, issued Apr. 3, 1990, which is incorporated herein by express reference. The running of tool strings on coiled tubing has the advantage that there are no threaded joints to be made up or broken out, so that the tools can be run much faster and at considerably less expense. U.S. Pat. No. 4,913,231 also discloses certain valve subsystems for opening and closing various ports and pressure passageways whereby inflatable packers can be expanded and retracted, and treating fluids injected into a zone that is isolated by the packers. Although such systems and subsystems represent considerable advances in the art, it would be highly useful and advantageous to have real-time surface read out of the values of certain downhole pressures, such as the pressure inside the coil tubing, hydrostatic pressure, packer inflation pressures, injection pressures, as well as other data such as downhole temperatures and the like. These measurements are significant because changing downhole well conditions during a treatment operation, which are not otherwise known at the surface without extensive calculations and assumptions, can cause unexpected failure of inflatable packers and/or tool operations. Of particular interest are inflatable packer pressure differentials to allow adjustments to be made at the surface which will maintain such differentials within design limits. Another variable of significance is the response of the reservoir rock to the treatment, which can be monitored if the pressure in the isolated zone is known so that the treatment can be adjusted to achieve optimum results. Other advantages for surface read-out of pressure as well as other variables will be apparent.
A general object of the present invention is to provide a new and improved well treating tool string and methods where various downhole measurements of interest can be made and monitored at the surface in real-time.
Another object of the present invention is to provide a new and improved well treating tool string having inflatable packers to isolate the treatment zone and where packer pressure differentials can be determined at the surface based upon real-time read-out of pressure data.